TORONTO — The overall number of prescriptions for opioids has increased over the last five years, but doctors have been giving patients fewer doses at one time, a report by the Canadian Institute for Health Information has found.

The report, released Wednesday, shows the number of opioid prescriptions rose by almost seven per cent between 2012 and 2016, while daily doses on average dropped by five per cent — to 226 million from 238 million.

Last year, 21.5 million prescriptions for the potent painkillers were dispensed, up from 20.2 million prescriptions in 2012, CIHI reported. Most were for chronic non-cancer pain relief.

“Opioid prescriptions are still going up, but the encouraging trend we’re seeing is the quantity of doses that are being dispensed is going down,” said Michael Gaucher, director of pharmaceuticals and health workforce information services at CIHI.

“When you put those two together, it’s encouraging in that the fewer doses being dispensed per prescription means that these drugs are being reviewed more regularly and potentially stopped or at least being assessed and switched perhaps to another mode of pain management,” he said.

However, the report also found that Canadians are increasingly being prescribed stronger opioids. In 2016, about 57 per cent of all opioids prescribed were high-potency; four years earlier, that figure was 52 per cent.

Canadians 65 and older were those most often prescribed opioids over the four-year period covered by the report, Gaucher said.

“When we looked at how often they were being prescribed in the different age groups, about one in five seniors received at least one opioid prescription in a given calendar year.”

CIHI data also show that one in eight seniors prescribed an opioid were put on a high-potency drug — such as oxycodone, morphine or the fentanyl patch — for 90 days or longer, he said, noting that the stronger opioids are generally used to relieve more severe pain.

“There are a lot of negative outcomes from prescribing opioids to seniors that go beyond death,” said Dr. Robert Strang, co-chair of the federal-provincial Special Advisory Committee on the Epidemic of Opioid Overdoses.

“There are substantive negative impacts on people’s lives,” Strang, Nova Scotia’s chief medical officer of health, said in a release.

Seniors are at greater risk for opioid-related harms due to several factors, including age-related changes in drug absorption and metabolism, and cognitive changes that may increase the risk of accidental drug poisoning.

The report said six types of the powerful narcotics — codeine, tramadol, oxycodone, hydromorphone, morphine and the fentanyl patch — accounted for more than 96 per cent of all opioids prescribed between 2012 and 2016. Of these, the last four are typically given for moderate to severe pain.

Gaucher said it’s unclear what’s driving the use of high-potency opioids, but the greying of the population and the attendant pain-inducing medical conditions that accrue with age could be a factor.

Since 2012, the number of prescriptions for strong opioids other than the fentanyl patch jumped by 19 per cent, while fentanyl prescriptions declined by almost seven per cent.

Gaucher doesn’t know why the fentanyl patch has fallen somewhat out of favour. But he speculated that the high number of overdose deaths, many linked to illicit fentanyl, may have raised both physician and patient awareness of the potency of the prescription form of the drug and its potential harms, leading to reduced use.

In June, the Public Health Agency of Canada reported 2,458 apparent opioid-related deaths for the previous year across the country (excluding Quebec). More than 900 of those fatalities occurred in British Columbia.

Concern over overdoses with a strong opioid such as the fentanyl patch may have left doctors wondering: “Is it the best choice or is there another choice that may be better?” Gaucher suggested.

CIHI also found that opioid prescribing practices varied across the country, with Quebec and British Columbia reporting the lowest number of daily doses per 1,000 residents (3,601 and 5,496, respectively) and Alberta (7,955) and Newfoundland and Labrador (7,878) the highest.

Quebec’s figure is not only the lowest in the country, it’s almost half of the Canadian average of 6,110 daily doses per 1,000 people.

“This new report rightly points out that we need to look at Quebec in much more detail and try to figure out why it’s so different from the rest of the country with regard to opioid prescribing,” said Strang.

While it’s not known why Quebec has such low dose-dispensing levels relative to the rest of the country, Gaucher said demographics, overall population health status and prescribing practices by physicians could all play a role.

“But part of it could just be increased awareness of prescribers and the attention they’re paying to managing pain with opioids, given the crisis situation.”

Both B.C. and Nova Scotia adopted opioid prescribing guidelines in 2015, and both experienced decreases in dispensing a year later, with daily doses per 1,000 population declining by almost 12 per cent in B.C. and by six per cent in Nova Scotia.

Strang said it would be ideal to see a marked reduction in the prescribing of all opioids, especially high-potency formulations.

“(But) we have to acknowledge that this is a balancing act,” he said. “While we’re trying to reduce the prescribing of opioids overall, we have to recognize that there are people who, for a very significant period of time, have been dependent on strong opioids.